Currently, except for the input method using handwriting on mobile device or touch pad such as on a tablet, the Chinese input methods using keyboard mainly include the Pinyin input method and the Five-Stroke input method (excluding the Zhuyin-Symbol input method used only by the Taiwanese). Most Chinese people have learnt Pinyin, so Pinyin input method is obviously in a dominant position, for the Chinese users can use the input method directly with no more learning required. As a matter of fact, although considerable time and effort are needed to learn and master the Five-Stroke, it is still widely used by people in China. The main reason for this is that the current Pinyin spellings used by the Pinyin input method only express syllables without tones. Today, the most popular Pinyin input methods are developed by large companies like Baidu, Sogou, Tencent QQ, Microsoft and Google, and all these methods let the user select the wanted Chinese character or word immediately after inputting the syllable spelling without the tone.
Mandarin Chinese has only about 410 syllables (not containing tones), but there are more than 3,000 commonly used Chinese characters, so when selecting the wanted Chinese character after inputting a syllable without tone, the user has to face an average of about 8 different commonly used Chinese characters (3300÷410, assuming there are a total of 3,300 commonly used Chinese characters). When inputting a character that is not commonly used, the selection situation is even worse. In general, the computer displays five characters for the user to choose from each time, and a key has to be pressed to display the next five, and so on. So it is quite time-consuming, and the selection situation is far worse than that of the Five-Stroke input method. Computer technology will, of course, place the more appropriate Chinese characters in the front to facilitate selection, but the help is limited.
Chinese patent No. ZL94117853.6 provides an HLV Pinyin input system, which uses the standard Western keyboard to input Chinese characters, inputting their syllables by their Pinyin spellings and their tones by the three letters h, l and v, with “no entry” representing the first tone, and h, l, v representing the second, third and fourth tones respectively. In this way, the invention allows simultaneous input of syllables and tones of Chinese characters to reduce repeated codes, thereby reducing the Chinese character selection time and improving the input speed. However, because inappropriate letters h, l and v are used to represent the tones in this invention, syllable boundary confusion occurs (see the disclosed specification of the invention from the bottom of Page 2 to the top of page 3). To remedy the confusion in this invention, extra letters need to be used to represent the four tones under different situations, so in addition to the letters h, l and v, extra letters y, w, r and k are used to represent the tones, resulting in complicacy (see claims 4-7 of the patent). Moreover, in addition to placement at the end of the syllable spellings, these letters representing the tones may sometimes need to be placed in other positions such as in front of n or ng.
No. ZL00119308.2 Chinese patent provides an improved HLV Pinyin input system. As before, it uses the standard Western keyboard to input Chinese characters. But in order to go further to reduce repeated codes, the invention introduces basic codes for the radicals of Chinese characters, so that it can simultaneously input the syllables, the tones and the radicals of Chinese characters. However, more than 240 radicals need to be set for this method, and each radical has its own basic code. This method successfully solves the problem of repeated code, but it becomes much more complex than before and is difficult to learn.